Recent statements from the US administration expressing an intention to acquire Greenland “one way or another” have transformed what was once dismissed as eccentric rhetoric into a genuine international legal concern.
Greenland is a self-governing territory, but sovereignty over it remains with Denmark, which retains responsibility for defence and foreign affairs and is internationally recognised as the sovereign state. That legal status has long been settled, including confirmation by the Permanent Court of International Justice in the landmark 1933 “Eastern Greenland Case” (Denmark v. Norway).
The rules governing territorial change are not ambiguous. Territory may be lawfully transferred only through consent, which is typically provided in a treaty of cession, and, where a people is concerned, through the free exercise of self-determination.
Modern international law rejects the idea that land may be taken by force. The Charter of the United Nations prohibits the use of force against the territorial integrity or political independence of any state. This is not a technical rule, it is part of the core of the international legal system established after World War 2 to ensure that conquest would never again be accepted as an instrument of state policy.
From this flows a second, equally fundamental rule: that territory that is acquired through aggression cannot be lawfully annexed or recognised. This prohibition emerged from the devastation of 20th-century wars of territorial conquest. For decades, it served as a stabilising constraint on international behaviour.
The Global South intimately understands the costs of a world where powerful states redraw maps at will. The prohibition on conquest is therefore not merely a European legal principle but a hard-won protective shield for states that lack overwhelming military power.
But recent conflicts (and an increasingly transactional rhetoric around territory) have placed that norm under strain. Russia’s invasion of Ukraine in 2022, involving the attempted forcible acquisition of sovereign territory, has become the most visible contemporary test of the rule against territorial conquest. Warnings of a possible forcible takeover of Taiwan illustrate how future challenges to that rule are now openly contemplated. As scholars have observed, when powerful states appear willing to test or erode the rule against territorial conquest, the entire web of sovereignty norms begins to weaken.
Greenland now sits uncomfortably within this moment. While the US’s interest in Greenland’s strategic position is not new, what distinguishes current developments is the refusal by senior US officials to exclude coercive means, including force, as a possible means of acquisition. European analysts have noted that this signalling could challenge the sovereignty of an EU and Nato member state, raising questions about how alliances respond when pressure comes from within.
International law permits territorial transfer only where both the sovereign state and the people concerned freely consent to the transfer. Greenlanders possess the right to self-determination, and the majority of the population have already expressed opposition to joining the US. Any attempt to induce, coerce, or pressure such consent would violate that right. Equally, any treaty that is concluded under coercion would be invalid. And, any use of armed force to obtain territory would constitute aggression and illegal annexation. No invocation of strategic necessity, resource security, or national interest provides a lawful justification, and these are precisely the rationales that international law was designed to restrain. The legal position is therefore straightforward: Greenland may be sold only with genuine consent.
It may not be coerced.
It may not be annexed by force.
It may not be taken.
At first glance, the matter of Greenland appears to be a European concern. But the stakes are global. For much of modern history, territorial conquest was the primary mechanism through which colonial empires expanded into Africa, Asia, Latin America, and the Pacific. The Global South intimately understands the costs of a world where powerful states redraw maps at will.
The prohibition on conquest is therefore not merely a European legal principle but a hard-won protective shield for states that lack overwhelming military power. Every state that could not withstand direct confrontation with a major military power has a material interest in preserving the rule against territorial acquisition by force. In practice, this means almost every state. If powerful actors are permitted to test territorial boundaries without legal consequence, weaker states face renewed exposure to coercion, fragmentation, and externally imposed political futures. The erosion of the conquest prohibition would not remain confined to Arctic geopolitics. It would echo across disputed borders, resource-rich regions, and strategically positioned small states, many of which are in the Global South.
Either states must insist that territorial integrity remains non-negotiable, regardless of who tests it, or they must accept a future in which power once again determines possession
The danger is not only in overt aggression but in inconsistency. When international law is enforced against some violators and ignored for others, its authority weakens. Scholars of international norms have warned that muted or selective responses to territorial seizures risk normalising incremental breaches. These seemingly “small” violations cumulatively erode once-firm rules.
If acquisition by coercion becomes conceivable in the case of Greenland, it becomes conceivable elsewhere. The precedent would matter far beyond Greenland. This is not an argument about Greenlandic politics, nor about the desirability of any particular strategic arrangement. It is about whether the international community will continue to treat territorial integrity as a binding rule or as a negotiable inconvenience.
For the states of the Global South, the answer carries existential weight. International law remains the only available equaliser in a system that is still marked by great asymmetries of power. When the rules prohibiting conquest weaken, hierarchy reasserts itself. When they hold, even the smallest states possess legal security against predation.
The rule against territorial conquest was never perfectly observed. But it has, for decades, prevented the return of a world in which borders change through force and where populations are transferred without consent. Its erosion would signal not only a legal shift but a moral regression.
The question of Greenland therefore offers us a moment of clarity. Either states must insist that territorial integrity remains non-negotiable, regardless of who tests it, or they must accept a future in which power once again determines possession. For the Global South, the choice is not abstract. It is the difference between a world governed by law, and one governed by appetite.
• Soni is a senior lecturer in the School of Law at the University of KwaZulu-Natal
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